Illustration of red blood cells moving through clogged artery to indicate cholesterol build up as a result of homozygous familial hypercholesterolemia
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Results from a UK Biobank study show people who develop coronary heart disease (CHD) have increased dementia risk in later life particularly those who develop heart disease before the age of 45 years.

Led by the Chinese Academy of Medical Sciences and Peking Union Medical College in Beijing, China, the Journal of the American Heart Association study analysis included more than 400,000 people enrolled in the UK Biobank.

The results showed that people in the study who had CHD diagnosed before the age of 45 years had 2.4-fold increased risk for developing later dementia compared with those with no CHD. Risks of dementia were still higher in individuals with a later diagnosis of CHD, but risks decreased the older the patients were on CHD diagnosis.

For example, people with a CHD diagnosis between 45 and 59 years had a 1.5-fold risk increase for developing future dementia and at 60 years or older a 1.1-fold risk increase compared with people with no CHD.

“CHD has previously been associated with dementia risk in older adults, however, this is believed to be the first large-scale study examining whether the age of CHD onset may impact the risk of developing dementia later in life,” said Fanfan Zheng, co-lead author and researcher in the School of Nursing at the Chinese Academy of Medical Sciences & Peking Union Medical College, in a press statement.

The study analysis included data from 432,667 adults enrolled in the UK Biobank aged 57 years on average. Of these, 50,685 (11.7%) had CHD. The CHD group were older, had higher body mass index, blood pressure and blood glucose levels and were less likely to be female. Many were also taking medications for treatment of CHD or diabetes.

Over a follow-up period of 12-13.6 years, there were 5876 cases of incident all-cause dementia, 2540 Alzheimer’s disease cases and 1220 cases of vascular dementia.

Biobank participants with CHD had a 36%, 13% and 78% increased risk for developing all-cause dementia, Alzheimer’s disease, or vascular dementia, respectively, compared with participants with no CHD.

However, age was a strong influencing factor, with higher risks associated with younger age at CHD onset. The highest risk was in people who developed CHD when aged younger than 45 years who had a 71%, 75%, and 65% increased risk of developing all-cause dementia, Alzheimer’s disease, or vascular dementia, respectively, compared with those aged 60 years or older at CHD onset.

“What surprised us most was the linear relationship between age at coronary heart disease onset and dementia. This shows the huge detrimental influence of premature coronary heart disease on brain health,” Zheng said.

“As more people live longer and are diagnosed with coronary heart disease at a younger age, it’s likely there will be a large increase in the number of people living with dementia in years to come. Health care professionals should be aware of individuals diagnosed with coronary heart disease at a young age. The next step is to determine whether modifying cardiovascular risk early in life will promote better brain health later in life.”

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